The suspected organizer of a Hezbollah bus bombing that killed five Israeli tourists and a local driver in Bulgaria last July has only tenuous links to Canada but still possessed a genuine Canadian passport, the National Post has learned.

After emigrating from Lebanon with his family and settling in British Columbia, the suspect became a naturalized Canadian citizen a decade ago. But when his parents divorced, he left Vancouver and returned with his mother to Lebanon at age 12.

Since then, he has returned to Canada only twice to visit family, but he still carried a Canadian passport — which he allegedly used to enter Bulgaria on June 28, 2012 to help orchestrate the bombing on behalf of the Lebanese terrorist group Hezbollah.

If confirmed by an RCMP investigation, his case could raise new questions about the tens of thousands of naturalized citizens who, despite living abroad and having only meagre ties to Canada, carry Canadian passports.

Matt Levitt, a leading U.S. expert on Hezbollah, said in an interview that after a string of failed attacks the terrorist group began actively seeking recruits with Western passports about three years ago.

“Hezbollah was told in early 2010 by Iran, ‘Go back and fix your operational security problems,'” said Mr. Levitt, a senior fellow at the Washington Institute for Near East Policy. “One thing that they did was they went out and they found these guys.”

More than 30 were also injured when the suicide bomber struck a tour bus parked at Sarafovo Airport in Burgas. Most of the victims were youths who had just arrived on a flight from Tel Aviv to vacation on the Black Sea.

On Tuesday, Bulgaria’s interior minister, Tsvetan Tsvetanov, told reporters a seven-month investigation had concluded the attack was the work of the bomber who died in the attack and two members of a Hezbollah cell — one Canadian and the other Australian.

He said the Canadian and Australian had entered Bulgaria three weeks before the attack using their genuine passports. They then began using fake Michigan driver’s licences — manufactured in Lebanon — to rent cars and hotel rooms.

“We have followed their entire activities in Australia and Canada so we have information about financing and their membership in Hezbollah,” he said in a statement on the Bulgarian interior ministry website. “A reasonable assumption can be made that the two of them were members of the militant wing of Hezbollah.”

Foreign Affairs Minister John Baird said Canada was working with Bulgarian authorities on the case. He identified the suspect as a “dual national living in Lebanon” but it was unclear whether the Canadian was currently in Lebanon.

“That Bulgaria has found convincing evidence of Hezbollah involvement in this carnage is, sadly, not surprising. It is yet more evidence of the depravity of Hezbollah,” Mr. Baird said. He called on the European Union to list Hezbollah as a terrorist organization.

The Bulgarians are the second government in less than a month to link major terrorist attacks in their countries to Canadians. Two weeks ago, Algerian Prime Minister Abdelmalik Sellal claimed two Canadians were involved in a siege at a gas plant that left 38 workers dead.

The National Post has independently verified that the suspected organizer of the attack is a naturalized Canadian citizen. His links to Hezbollah remain unclear but the Iranian-backed Shi’ite terrorist group has long been active in Canada.

According to a Canadian intelligence report recently released to the Post: “Hezbollah has had a presence in Canada … Hezbollah supporters conduct fundraising, procurement and intelligence activities in Canada, and are involved in organized crime, including fraud.

“Hezbollah continues to threaten retaliation against Israeli interests worldwide for the killing of key individuals in the past two years,” reads the report by the government’s Integrated Terrorism Assessment Centre.

The bus attack at the Sarafovo Airport in Burgas was one of several attempts to strike Israelis around the world as Iran — Hezbollah’s state sponsor — was under international pressure over its rogue nuclear program.

A second declassified intelligence report, dated five months before the Burgas attack, said Hezbollah had already made 10 attempts to attack Israeli interests abroad, partly to retaliate for the 2008 death of Hezbollah’s chief terrorist Imad Mugniyah, who was killed by a bomb planted in his car in Damascus.